> Henri Menke <mailto:henrimenke@gmail.com>
> 25. August 2016 um 15:31
> Hi Jan,
>
> unfortunately, these commands are in no book. I just looked them up in 
> the ConTeXt source. However, these two books helped me a lot in 
> improving my understanding of TeX and ConTeXt. They are definitely 
> worth their money!
>
> The TeXbook by Donald E. Knuth https://amzn.com/0201134489
> Programming in Lua by Roberto Ierusalimschy https://amzn.com/859037985X
Other good books for TeX are

   - TeX by Topic (https://www.ctan.org/pkg/texbytopic) and
   - TeX for the Impatient (https://www.ctan.org/pkg/impatient)

Wolfgang